1. FIELD OF THE INVENTION
The present invention relates to a cutter of a tip dresser for use in dressing a tip or electrode of a welding apparatus.
2. DESCRIPTION OF THE PRIOR ART
A dresser is known up to now, which employs two or three blades as a cutter for dressing a tip of a welding apparatus. Such a dresser is disclosed for example in Japanese Laid-Open Utility Model Publication No. 54946/82, wherein, as shown in FIGS. 4 and 5 herein, the dresser employs a double-edged cutter comprising a flat portion 3 having blades 1 constituting the cutter each with a pointed tip centered at a central point 2 as well as an upstanding portion 4 rising outwardly of the flat portion 3, thereby forming a cutter end which is dish-shaped in cross section.
The prior three piece blade structure has as described above the pointed tips of the respective blades 1 centered at the central point 2. Accordingly, each of the blades can have a front relief angle formed thereon upon forming the cutting blade, but not a rake angle characterizing the cutting blade in the vicinity of the central point. Thus, the cutting capability of the cutter near its flat portion 3, particularly in the vicinity of the central position point 2 thereof is extremely reduced. Namely, the flat surface of the pointed end of the electrode or tip can not be cut uniformly, particularly in its central portion, 50 the pointed end can not be cut as desired. As a result, a desired shape of the tip can not be achieved.